The Asahi Shimbun reported in March on the decision of four big Japanese electric utilities to decommission a total of five nuclear reactors that have been in operation for more than 40 years. Respective plans have been submitted to the Ministry of Economy, Trade and Industry (METI). “This is the first application of the regulation [- a rule change prompted by the 2011 Fukushima nuclear accident] that, in principle, limits the operation of nuclear reactors to 40 years,” the paper’s editorial page writes.

Interestingly, almost “20 of Japan’s 48 commercial [operational] nuclear reactors have been in service for 30 years or longer” and utilities thus “get a one-time-only chance to extend operations beyond 40 years,” the Asahi Shimbun explains further. Note, prior to the 2011 nuclear accident, Japan had 54 operational nuclear reactors. Moreover, 24 nuclear reactors are now under Nuclear Regulation Authority (NRA) review, which also includes the – officially under construction – Ohma Advanced Boiling Water Reactor (ABWR), according to a World Nuclear Industry Status report.

With persistent public wariness and the Japanese Nuclear Regulation Authority under heavy scrutiny, nuclear reactors under consideration and those up for operational license extension are under the microscope. Not only will they have to pass rigorous inspections but these reactors will “require further investments”. “As the reactors continue to age, the utilities will have to make up their minds from year to year,” the Asahi Shimbun suggests.

Meanwhile, the US seems to embark on a different strategy leading in the opposite direction with regard to aging plants and license extensions. The US regulator (NRC) started the process of extending original 40-year licenses – thereby assessing whether a 20-year license renewal for reactors in question can be granted on a case-by-case basis – which would bring a typical US nuclear power plant’s lifespan up to 60 years of operation.

For more insight, read the “Breaking Energy US Nuclear Investigation,” a series of articles, here, here and here.

In Japan’s case we can observe an “unholy trinity” developing – a term borrowed and modified from the term “holy trinity” originally formulated to better understand the challenge of monetary policy formulation. Ramping back up some Japanese nuclear capacity does not occur in a policy vacuum and therefore will significantly impact Japan’s greenhouse has emissions reduction target via how much fossil fuel (LNG, coal) will need to replace ‘idled’ nuclear capacity. The issue is compounded given that a wide-range expansion of renewables is hampered by very ‘Japan-specific’ constraints.

To put this into perspective, at the 2015 Columbia Global Energy Summit hosted by the Center on Global Energy Policy at Columbia University’s SIPA, Shigeru Muraki – Member of the Board and Executive Advisor of Tokyo Gas – discussed some of the problems associated with siting wind parks and connecting renewables to the Japanese power grid. In his view, both factors will have an impact on the future share of renewables in Japan.

It is also crucial to remember the interplay of concerns over energy security, economic efficiency in terms of electricity costs to preserve Japanese companies’ international competitiveness, environmental impact as well as safety are driving Japanese energy policy in general. Reverting back to the “unholy trinity”, Mr. Shigeru Muraki remarked that restarting all 24 nuclear units in Japan would take in his estimation between four to six years if the regulatory process runs smoothly.

Most importantly, he added projections that see renewables account for about 20 percent of electricity generation by 2030 and nuclear energy for 20-23 percent are predicated on the assumption that Japanese nuclear power plants have their lifetimes extended by the regulator from 40 years to 60 years. If this were to stop, Mr. Shigeru Muraki elaborated further, the share of nuclear power would drop to less than 15 per cent. In that case, even with an optimistic 20 percent contribution from renewables, fossil fuels would suddenly have to supply the remaining 65 percent of power generation. Consequently, there seems no viable path to a “climate-friendly” post-2020 reduction in emissions without a significant contribution from – in climate terms – “clean” nuclear energy in Japan.